This invention relates to a panel for an enclosure that shields electronic components from electromagnetic interference and/or prevents the emission of electromagnetic radiation.
It is known to provide such an enclosure with one door in the form of a removable side panel that is held in place by a large number of screws and has between itself and the body of the enclosure a gasket to create a seal. The system has a number of disadvantages, such as that entering the enclosure, to maintain the electronic components for example, is a tedious process; and, over time, the gasket deteriorates and so the quality of the seal and thereby the effectiveness of the enclosure reduce.
EP-A-0781080 discloses an hermetically sealed and electromagnetically shielded casing to house electronic components. The casing comprises a casing body, which is trough-shaped and has a circumferential, preferably overhanging, edge, and a casing lid which fits against the circumferential edge of the casing body, encloses it, and with its edge presses against the outer wall of the casing body. The casing lid can also fit against the inner wall of the casing body and press against the inner wall. The casing lid has a ring-pull to open the casing. At a distance from the inner wall of the casing body, the casing lid has an external stamped strip to take an auxiliary tool, preferably a tin opener. The use of metal material for both casing components electromagnetically shields the casing. Tinplate, aluminium or a similar thin-walled material is used to give both minimum dimensions and light weight. The stamped strip takes the auxiliary tool, to allow the casing lid to be slit at given points and partially pulled away from the casing using the ring-pull. The casing can be opened in this way. The casing may be sheathed in plastic.
FR-A-894705 discloses a screening box which is electrically sealed at a joint. The electrically sealed joint is obtained by folding two sheet metal pieces at their edges to form U-channels engaged one in the other in such manner that the exterior surface of one of the edges presses resiliently against the interior surface of the other edge.
U.S. Pat. No. 5,278,351 discloses a personal computer cabinet with a cabinet base, an integral rear panel, a front panel, and two upwardly extending lips from the base. A cabinet cover engages with the front panel, the rear panel and includes two spring channel clips which engage with the lips of the base to negate or minimize any electromagnetic interference radiations from the electrical components inside a computer housing. A flexible sealing gasket may be provided between each base lip and the adjacent side of the cabinet cover and is held in place by spring pressure from the adjacent spring channel clip to effect an hermetic seal.
According to the present invention, there is provided a shielding enclosure for electronic components, comprising a hollow body, said hollow body having a sheet metal wall portion and an opening closed by a readily-removable sheet metal panel, with interdigitation between an edge zone of said wall portion and an adjacent edge zone of said panel, said interdigitation constituting a U-section channel on one of said wall portion and said panel and an interdigitating edge on the other of said wall portion and said panel, said U-section channel being integral with said one of said wall portion and said panel, and the arrangement being such that, when said panel is opened, relative movement between said interdigitating edge and said U-section channel is thereby produced.
Owing to the interdigitation, since electromagnetic radiation travels in straight lines, it cannot pass between those edge zones. Moreover, the panel is readily openable and readily re-closable.
In a preferred embodiment, the enclosure is generally of the shape of a rectangular parallelepiped and comprises a frame carrying panels on all six sides, with such interdigitation provided along all edges of the shape. On the other hand, if there are edges at which such panels are integral with each other, such interdigitation is not provided at those edges. At least one of the panels is readily openable, for example is locked or latched to the enclosure body and/or is attached thereto by a few screws, with any other panels being permanently fixed to the frame. The or each openable panel may be in the form of a door hingedly mounted at one edge region and having over at least part of its periphery a flange which mates with a U-section channel provided by the adjacent edge zones of the adjacent wall portions.